1. Field of the Invention
The present invention relates generally to a cover plate arrangement for a well such as a water well and, more specifically, to a cover plate arrangement for a well which is quickly and easily centered above an exposed well bore and which is held securely in place by an associated well pump once in position on the well.
2. Description of the Prior Art
Modern water wells are drilled into the ground with the well bore either being uncased, or being protected by a casing which is sunk into the well. Typically, a submersible pump is then run down the well bore on either rigid or flexible tubing and submerged in water located at the bottom of the well. The pump provides water to the surface through the flexible tubing which is connected to the pump and which leads up the well bore to the well surface. Although various types of flexible tubing are known, the most commonly used tubing today is a polyolefin, such as polyethylene. In certain of the prior art practices, a separate safety rope or cable is also provided, connected to the pump and extending the length of the bore to assist in withdrawal of the submersible pump from the well bore if the pipe were to separate or break. In addition, since the submersible pump is electrically driven, a power cord or cable also typically extends from the well surface down the bore to the pump where it is attached to the flexible tubing, as by taping the cable to the tubing.
The present invention has general applicability to “cased” wells of the type described above where cylindrical tubing in the form of steel pipe is inserted into the well shaft which has been formed to serve as the side walls of the well. Typically a short portion of this casing is either flush with, or extends slightly above the ground as the upper terminal of the well, which must be covered to prevent foreign matter from entering the well. Although a cased well of the type previously described is commonly encountered in the field, it will be understood upon further reading of the present specification that the invention being described also has applicability to uncased wells which must also be covered with some type of well cover plate arrangement, or to well heads which have a concrete pad or the like poured at the well surface to form the well opening.
In any event, whatever the particular configuration of the well head or well opening, a well cover plate arrangement of some type is generally needed to provide security for the well to prevent the entry of foreign matter, and also to provide provision for passing the flexible tubing, electrical cable, and other accessory lines to the down hole pump which is submerged in the well. Since the well cover plate provides provisions for passing tubing to the pump, which is submerged in the well, the cover must be easily removed so that the pump can be replaced or repaired when necessary, and the cover must be generally centered on the casing in order to center the pump in the well.
While simple devices such as a plate with the required openings conceivably could be permanently welded or otherwise affixed to the top end of a well casing, the fact that the submersible pumps fail and sometimes must be replaced dictates that some form of removable seal or cap be provided. As a result, a variety of different types and styles of removable well cover plates have been provided in the industry, such as those shown in Zanin, U.S. Pat. No. 2,735,697, Medina, U.S. Pat. No. 3,631,895, Martin, U.S. Pat. No. 3,963,054, Henson, U.S. Pat. No. 4,129,151, Forsell, U.S. Pat. No. 4,202,376, and Henson, U.S. Pat. No. 4,972,905. However, the devices shown in the prior art, such as those included above, have all generally involved complicated and sophisticated clamping and centering means, which are prohibitively expensive for use in many instances, such as in a single family water well. In addition the complexity of these devices greatly adds to the difficulty in installing and removing the cover, and results in a high rate of failure when the cover is repeatedly removed and installed.
Some well casings use successive threaded sections of pipe, while others have successive sections welded together. While it is theoretically possible in threaded casing installations to provide a removable well cap which threadedly engages threads provided at the upper end of the well casing, caps which thread onto the well casing are deemed impractical for a number of reasons. Turning a threaded cap to install it would undesirably twist the electrical cable which must pass through it, unless the cable passed through an opening in the cap so large that insects or rainwater could also pass through the opening. Also, prohibitively great forces often would be required to unscrew a threaded cap which had been exposed to weather for some years. For such reasons, practical removable well caps cannot be threaded onto the upper ends of well casings.
It is also advantageous that well cover plate arrangements not employ a plurality of bolts or nuts in securing the cover plate to the well head since the bolts and nuts frequently must be installed under adverse weather conditions. If bolts or nuts are accidentally dropped they are frequently lost in mud, snow or the like at a well side. Where some sort of bolt and nut arrangement is spaced about the well cover, their threads sometimes become jammed or may be inadvertently stripped, sometimes ruining the whole assembly unless it is re-bored and re-tapped with a larger threaded hole, or sometimes requiring that spare bolts or nuts be obtained. A further disadvantage of seals using plural bolts and nuts spaced around the cover plate is that they must be tightened evenly, i.e. by tightening a given bolt only partially and then proceeding to similarly tighten each of the other bolts before further tightening the given bolt. This is a time consuming and somewhat tedious procedure at best.
It is the object of the present invention to provide an improved well cover plate arrangement which overcomes the various mentioned disadvantages of the prior art by providing a combination U-plate and door element of unique design which are economical to manufacture and which can be easily installed under field conditions.
It is a further object of the present invention to provide an improved combination U-plate and door element, each of which is of a “single-piece” nature, the plates being formed from readily available materials utilizing simple manufacturing techniques.
It is a further object of the invention to provide an improved well cover plate arrangement which does not require sequential tightening of a plurality of bolts and/or nuts in order to install the assembly.
The provision of such a well cover plate arrangement allows a well cover assembly to be installed or removed much more rapidly than prior assemblies, generally requiring only a single worker, thereby providing a significant savings in labor costs.